// assumes main class is last declared class
// returns actual CNC
static L<S> findMainClass(L<S> tok) {
  for (L<S> c : reversedList(allClasses(tok))) {
    S name = getClassDeclarationName(c);
    if (eq(name, "main") || name.startsWith("x"))
      return c;
  }
  ret findBlock("m {", tok);
}